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<a href="util__fwd_8hpp.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a id="l00001" name="l00001"></a><span class="lineno">    1</span><span class="comment">/* Flow-IPC: Core</span></div>
<div class="line"><a id="l00002" name="l00002"></a><span class="lineno">    2</span><span class="comment"> * Copyright 2023 Akamai Technologies, Inc.</span></div>
<div class="line"><a id="l00003" name="l00003"></a><span class="lineno">    3</span><span class="comment"> *</span></div>
<div class="line"><a id="l00004" name="l00004"></a><span class="lineno">    4</span><span class="comment"> * Licensed under the Apache License, Version 2.0 (the</span></div>
<div class="line"><a id="l00005" name="l00005"></a><span class="lineno">    5</span><span class="comment"> * &quot;License&quot;); you may not use this file except in</span></div>
<div class="line"><a id="l00006" name="l00006"></a><span class="lineno">    6</span><span class="comment"> * compliance with the License.  You may obtain a copy</span></div>
<div class="line"><a id="l00007" name="l00007"></a><span class="lineno">    7</span><span class="comment"> * of the License at</span></div>
<div class="line"><a id="l00008" name="l00008"></a><span class="lineno">    8</span><span class="comment"> *</span></div>
<div class="line"><a id="l00009" name="l00009"></a><span class="lineno">    9</span><span class="comment"> *   https://www.apache.org/licenses/LICENSE-2.0</span></div>
<div class="line"><a id="l00010" name="l00010"></a><span class="lineno">   10</span><span class="comment"> *</span></div>
<div class="line"><a id="l00011" name="l00011"></a><span class="lineno">   11</span><span class="comment"> * Unless required by applicable law or agreed to in</span></div>
<div class="line"><a id="l00012" name="l00012"></a><span class="lineno">   12</span><span class="comment"> * writing, software distributed under the License is</span></div>
<div class="line"><a id="l00013" name="l00013"></a><span class="lineno">   13</span><span class="comment"> * distributed on an &quot;AS IS&quot; BASIS, WITHOUT WARRANTIES OR</span></div>
<div class="line"><a id="l00014" name="l00014"></a><span class="lineno">   14</span><span class="comment"> * CONDITIONS OF ANY KIND, either express or implied.</span></div>
<div class="line"><a id="l00015" name="l00015"></a><span class="lineno">   15</span><span class="comment"> * See the License for the specific language governing</span></div>
<div class="line"><a id="l00016" name="l00016"></a><span class="lineno">   16</span><span class="comment"> * permissions and limitations under the License. */</span></div>
<div class="line"><a id="l00017" name="l00017"></a><span class="lineno">   17</span><span class="comment"></span> </div>
<div class="line"><a id="l00018" name="l00018"></a><span class="lineno">   18</span><span class="comment">/// @file</span></div>
<div class="line"><a id="l00019" name="l00019"></a><span class="lineno">   19</span><span class="comment"></span><span class="preprocessor">#pragma once</span></div>
<div class="line"><a id="l00020" name="l00020"></a><span class="lineno">   20</span> </div>
<div class="line"><a id="l00021" name="l00021"></a><span class="lineno">   21</span><span class="preprocessor">#include &quot;<a class="code" href="native__handle_8hpp.html">ipc/util/native_handle.hpp</a>&quot;</span></div>
<div class="line"><a id="l00022" name="l00022"></a><span class="lineno">   22</span><span class="preprocessor">#include &quot;<a class="code" href="common_8hpp.html">ipc/common.hpp</a>&quot;</span></div>
<div class="line"><a id="l00023" name="l00023"></a><span class="lineno">   23</span><span class="preprocessor">#include &lt;flow/log/log.hpp&gt;</span></div>
<div class="line"><a id="l00024" name="l00024"></a><span class="lineno">   24</span><span class="preprocessor">#include &lt;flow/async/util.hpp&gt;</span></div>
<div class="line"><a id="l00025" name="l00025"></a><span class="lineno">   25</span><span class="preprocessor">#include &lt;boost/asio.hpp&gt;</span></div>
<div class="line"><a id="l00026" name="l00026"></a><span class="lineno">   26</span><span class="preprocessor">#include &lt;boost/interprocess/permissions.hpp&gt;</span></div>
<div class="line"><a id="l00027" name="l00027"></a><span class="lineno">   27</span><span class="preprocessor">#include &lt;boost/interprocess/creation_tags.hpp&gt;</span></div>
<div class="line"><a id="l00028" name="l00028"></a><span class="lineno">   28</span><span class="comment"></span> </div>
<div class="line"><a id="l00029" name="l00029"></a><span class="lineno">   29</span><span class="comment">/**</span></div>
<div class="line"><a id="l00030" name="l00030"></a><span class="lineno">   30</span><span class="comment"> * Flow-IPC module containing miscellaneous general-use facilities that ubiquitously used by ~all Flow-IPC modules</span></div>
<div class="line"><a id="l00031" name="l00031"></a><span class="lineno">   31</span><span class="comment"> * and/or do not fit into any other Flow-IPC module.</span></div>
<div class="line"><a id="l00032" name="l00032"></a><span class="lineno">   32</span><span class="comment"> *</span></div>
<div class="line"><a id="l00033" name="l00033"></a><span class="lineno">   33</span><span class="comment"> * Each symbol therein is typically used by at least 1 other Flow-IPC module; but all public symbols (except ones</span></div>
<div class="line"><a id="l00034" name="l00034"></a><span class="lineno">   34</span><span class="comment"> * under a detail/ subdirectory) are intended for use by Flow-IPC user as well.  Some particulars to note:</span></div>
<div class="line"><a id="l00035" name="l00035"></a><span class="lineno">   35</span><span class="comment"> *</span></div>
<div class="line"><a id="l00036" name="l00036"></a><span class="lineno">   36</span><span class="comment"> * ipc::util::Shared_name is a universally used shared-resource name class, conceptually similar to</span></div>
<div class="line"><a id="l00037" name="l00037"></a><span class="lineno">   37</span><span class="comment"> * `boost::filesystem::path`.  It is used in ipc::transport APIs -- namely to name endpoints when establishing channels,</span></div>
<div class="line"><a id="l00038" name="l00038"></a><span class="lineno">   38</span><span class="comment"> * and more -- but also in other Flow-IPC modules.  For example `Shared_name` is used to name certain SHM entities</span></div>
<div class="line"><a id="l00039" name="l00039"></a><span class="lineno">   39</span><span class="comment"> * in ipc::shm and in ipc::session when connecting to conversation partner process(es).</span></div>
<div class="line"><a id="l00040" name="l00040"></a><span class="lineno">   40</span><span class="comment"> *</span></div>
<div class="line"><a id="l00041" name="l00041"></a><span class="lineno">   41</span><span class="comment"> * ipc::util::Native_handle is a commonly used native-handle (FD in POSIX parlance) wrapper (so thin it doesn&#39;t add</span></div>
<div class="line"><a id="l00042" name="l00042"></a><span class="lineno">   42</span><span class="comment"> * a single bit on top of the actul FD).  These are ~always passed around by value (copied), as they are very small</span></div>
<div class="line"><a id="l00043" name="l00043"></a><span class="lineno">   43</span><span class="comment"> * in practice.</span></div>
<div class="line"><a id="l00044" name="l00044"></a><span class="lineno">   44</span><span class="comment"> *</span></div>
<div class="line"><a id="l00045" name="l00045"></a><span class="lineno">   45</span><span class="comment"> * There are of course various other things; just check them out as they are referenced, or just look around.</span></div>
<div class="line"><a id="l00046" name="l00046"></a><span class="lineno">   46</span><span class="comment"> * Note there are free functions providing various niceties; and more types including classes and scoped `enum`s.</span></div>
<div class="line"><a id="l00047" name="l00047"></a><span class="lineno">   47</span><span class="comment"> */</span></div>
<div class="line"><a id="l00048" name="l00048"></a><span class="lineno">   48</span><span class="keyword">namespace </span><a class="code hl_namespace" href="namespaceipc_1_1util.html">ipc::util</a></div>
<div class="line"><a id="l00049" name="l00049"></a><span class="lineno">   49</span>{</div>
<div class="line"><a id="l00050" name="l00050"></a><span class="lineno">   50</span> </div>
<div class="line"><a id="l00051" name="l00051"></a><span class="lineno">   51</span><span class="comment">// Types.</span></div>
<div class="line"><a id="l00052" name="l00052"></a><span class="lineno">   52</span> </div>
<div class="line"><a id="l00053" name="l00053"></a><span class="lineno">   53</span><span class="comment">// Find doc headers near the bodies of these compound types.</span></div>
<div class="line"><a id="l00054" name="l00054"></a><span class="lineno">   54</span> </div>
<div class="line"><a id="l00055" name="l00055"></a><span class="lineno">   55</span><span class="keyword">template</span> &lt;<span class="keyword">typename</span> T, <span class="keyword">typename</span> Allocator = std::allocator&lt;T&gt;&gt;</div>
<div class="line"><a id="l00056" name="l00056"></a><span class="lineno">   56</span><span class="keyword">class </span>Default_init_allocator;</div>
<div class="line"><a id="l00057" name="l00057"></a><span class="lineno">   57</span> </div>
<div class="line"><a id="l00058" name="l00058"></a><span class="lineno">   58</span><span class="keyword">class </span>Use_counted_object;</div>
<div class="line"><a id="l00059" name="l00059"></a><span class="lineno">   59</span> </div>
<div class="line"><a id="l00060" name="l00060"></a><span class="lineno">   60</span><span class="comment">/* Normally we&#39;d try to forward-declare the following only, but doing so means (1) having to specify `: size_t`</span></div>
<div class="line"><a id="l00061" name="l00061"></a><span class="lineno">   61</span><span class="comment"> * in two places, here and the definition; and (2) ::S_END_SENTINEL cannot be used in _fwd.hpp to, say,</span></div>
<div class="line"><a id="l00062" name="l00062"></a><span class="lineno">   62</span><span class="comment"> * set a compile-time array&lt;&gt; size.  So just make an exception and define the enum fully here.  It&#39;s not</span></div>
<div class="line"><a id="l00063" name="l00063"></a><span class="lineno">   63</span><span class="comment"> * &quot;really&quot; an aggregate type (class), so it&#39;s all right. */</span></div>
<div class="line"><a id="l00064" name="l00064"></a><span class="lineno">   64</span> </div>
<div class="line"><a id="l00065" name="l00065"></a><span class="lineno">   65</span><span class="preprocessor">#ifndef FLOW_OS_LINUX</span></div>
<div class="line"><a id="l00066" name="l00066"></a><span class="lineno">   66</span><span class="keyword">static_assert</span>(<span class="keyword">false</span>, <span class="stringliteral">&quot;Design of Permissions_level assumes a POSIX-y security model with users and groups; &quot;</span></div>
<div class="line"><a id="l00067" name="l00067"></a><span class="lineno">   67</span>                       <span class="stringliteral">&quot;we have not yet considered whether it can apply to Windows in its current form.  &quot;</span></div>
<div class="line"><a id="l00068" name="l00068"></a><span class="lineno">   68</span>                       <span class="stringliteral">&quot;Should work in non-Linux POSIX OS (like macOS) but must be checked/tested.&quot;</span>);</div>
<div class="line"><a id="l00069" name="l00069"></a><span class="lineno">   69</span><span class="preprocessor">#endif</span></div>
<div class="line"><a id="l00070" name="l00070"></a><span class="lineno">   70</span><span class="comment"></span> </div>
<div class="line"><a id="l00071" name="l00071"></a><span class="lineno">   71</span><span class="comment">/**</span></div>
<div class="line"><a id="l00072" name="l00072"></a><span class="lineno">   72</span><span class="comment"> * Simple specifier of desired access permissions, usually but not necessarily translated into</span></div>
<div class="line"><a id="l00073" name="l00073"></a><span class="lineno">   73</span><span class="comment"> * a `Permissions` value (though even then different value in different contexts).  May be used to map, say,</span></div>
<div class="line"><a id="l00074" name="l00074"></a><span class="lineno">   74</span><span class="comment"> * from a Permissions_level to a #Permissions value in an</span></div>
<div class="line"><a id="l00075" name="l00075"></a><span class="lineno">   75</span><span class="comment"> * `array&lt;Permissions, size_t(Permissions_level::S_END_SENTINEL)&gt;`.</span></div>
<div class="line"><a id="l00076" name="l00076"></a><span class="lineno">   76</span><span class="comment"> *</span></div>
<div class="line"><a id="l00077" name="l00077"></a><span class="lineno">   77</span><span class="comment"> * While, unlike #Permissions, this `enum` intends not be overtly based on a POSIX RWXRWXRWX model, it does</span></div>
<div class="line"><a id="l00078" name="l00078"></a><span class="lineno">   78</span><span class="comment"> * still assume the 3 user groupings are &quot;user themselves,&quot; &quot;user&#39;s group,&quot; and &quot;everyone.&quot;  The 1st and 3rd</span></div>
<div class="line"><a id="l00079" name="l00079"></a><span class="lineno">   79</span><span class="comment"> * are likely universal, but the 2nd may not apply to all OS -- through probably all POSIX/Unix ones --</span></div>
<div class="line"><a id="l00080" name="l00080"></a><span class="lineno">   80</span><span class="comment"> * and even for something like Linux there could be different groupings such as ones based on OS ACL.</span></div>
<div class="line"><a id="l00081" name="l00081"></a><span class="lineno">   81</span><span class="comment"> * As of this writing it&#39;s fine, as this is a POSIX-targeted library at least (in fact, Linux, as of this writing,</span></div>
<div class="line"><a id="l00082" name="l00082"></a><span class="lineno">   82</span><span class="comment"> * but that could change to include, say, macOS/similar).</span></div>
<div class="line"><a id="l00083" name="l00083"></a><span class="lineno">   83</span><span class="comment"> *</span></div>
<div class="line"><a id="l00084" name="l00084"></a><span class="lineno">   84</span><span class="comment"> * @internal</span></div>
<div class="line"><a id="l00085" name="l00085"></a><span class="lineno">   85</span><span class="comment"> * ### Maintenance ###</span></div>
<div class="line"><a id="l00086" name="l00086"></a><span class="lineno">   86</span><span class="comment"> * Do *not* change the order of these constants unless absolutely necessary.  In general any change here</span></div>
<div class="line"><a id="l00087" name="l00087"></a><span class="lineno">   87</span><span class="comment"> * means updating any `array&lt;&gt;`s (etc.) that map implicitly from a `size_t` representing</span></div>
<div class="line"><a id="l00088" name="l00088"></a><span class="lineno">   88</span><span class="comment"> * Permissions_level.  By convention they are named `*_PERMISSIONS_LVL_MAP` as of this writing.</span></div>
<div class="line"><a id="l00089" name="l00089"></a><span class="lineno">   89</span><span class="comment"> *</span></div>
<div class="line"><a id="l00090" name="l00090"></a><span class="lineno">   90</span><span class="comment"> * The `array&lt;&gt;` mapping scheme is for max performance; if one uses an `unordered_map` or similar, then there is no</span></div>
<div class="line"><a id="l00091" name="l00091"></a><span class="lineno">   91</span><span class="comment"> * similar issue.</span></div>
<div class="line"><a id="l00092" name="l00092"></a><span class="lineno">   92</span><span class="comment"> */</span></div>
<div class="line"><a id="l00093" name="l00093"></a><span class="lineno"><a class="line" href="namespaceipc_1_1util.html#a2ec0bfdddb41a1ef0403e4bb8967705d">   93</a></span><span class="keyword">enum class</span> <a class="code hl_enumeration" href="namespaceipc_1_1util.html#a2ec0bfdddb41a1ef0403e4bb8967705d">Permissions_level</a> : <span class="keywordtype">size_t</span></div>
<div class="line"><a id="l00094" name="l00094"></a><span class="lineno">   94</span>{<span class="comment"></span></div>
<div class="line"><a id="l00095" name="l00095"></a><span class="lineno">   95</span><span class="comment">  /// Forbids all access, even by the creator&#39;s user.  Most likely this would be useful for testing or debugging.</span></div>
<div class="line"><a id="l00096" name="l00096"></a><span class="lineno">   96</span><span class="comment"></span>  <a class="code hl_enumvalue" href="namespaceipc_1_1util.html#a2ec0bfdddb41a1ef0403e4bb8967705dac43e9194d6c0e9803ecabbf3cb4c97fa">S_NO_ACCESS</a>,</div>
<div class="line"><a id="l00097" name="l00097"></a><span class="lineno">   97</span><span class="comment"></span> </div>
<div class="line"><a id="l00098" name="l00098"></a><span class="lineno">   98</span><span class="comment">  /// Allows access by resource-owning user (in POSIX/Unix identified by UID) and no one else.</span></div>
<div class="line"><a id="l00099" name="l00099"></a><span class="lineno">   99</span><span class="comment"></span>  <a class="code hl_enumvalue" href="namespaceipc_1_1util.html#a2ec0bfdddb41a1ef0403e4bb8967705daa3e1d310128f18fe2f903bf3cba8849a">S_USER_ACCESS</a>,</div>
<div class="line"><a id="l00100" name="l00100"></a><span class="lineno">  100</span><span class="comment"></span> </div>
<div class="line"><a id="l00101" name="l00101"></a><span class="lineno">  101</span><span class="comment">  /**</span></div>
<div class="line"><a id="l00102" name="l00102"></a><span class="lineno">  102</span><span class="comment">   * Allows access by resource-owning user&#39;s containing group(s) (in POSIX/Unix identified by GID) and no one else.</span></div>
<div class="line"><a id="l00103" name="l00103"></a><span class="lineno">  103</span><span class="comment">   * This implies, as well, at least as much access as `S_USER_ACCESS`.</span></div>
<div class="line"><a id="l00104" name="l00104"></a><span class="lineno">  104</span><span class="comment">   */</span></div>
<div class="line"><a id="l00105" name="l00105"></a><span class="lineno">  105</span>  <a class="code hl_enumvalue" href="namespaceipc_1_1util.html#a2ec0bfdddb41a1ef0403e4bb8967705daa5508fa6037b9c0926cf7eb20af97a6d">S_GROUP_ACCESS</a>,</div>
<div class="line"><a id="l00106" name="l00106"></a><span class="lineno">  106</span><span class="comment"></span> </div>
<div class="line"><a id="l00107" name="l00107"></a><span class="lineno">  107</span><span class="comment">  /// Allows access by all.  Implies, as well, at least as much access as `S_GROUP_ACCESS` and thus `S_USER_ACCESS`.</span></div>
<div class="line"><a id="l00108" name="l00108"></a><span class="lineno">  108</span><span class="comment"></span>  <a class="code hl_enumvalue" href="namespaceipc_1_1util.html#a2ec0bfdddb41a1ef0403e4bb8967705da25bf1cdee66ff5f73914fd5b0ee996e9">S_UNRESTRICTED</a>,</div>
<div class="line"><a id="l00109" name="l00109"></a><span class="lineno">  109</span><span class="comment"></span> </div>
<div class="line"><a id="l00110" name="l00110"></a><span class="lineno">  110</span><span class="comment">  /// Sentinel: not a valid value.  May be used to, e.g., size an `array&lt;&gt;` mapping from Permissions_level.</span></div>
<div class="line"><a id="l00111" name="l00111"></a><span class="lineno">  111</span><span class="comment"></span>  <a class="code hl_enumvalue" href="namespaceipc.html#a4ccdeed058222c635745a4dc830e99f7a6fba12db09e5bebfaa04f6372c41c2cf">S_END_SENTINEL</a></div>
<div class="line"><a id="l00112" name="l00112"></a><span class="lineno">  112</span>}; <span class="comment">// enum class Permissions_level</span></div>
<div class="line"><a id="l00113" name="l00113"></a><span class="lineno">  113</span><span class="comment"></span> </div>
<div class="line"><a id="l00114" name="l00114"></a><span class="lineno">  114</span><span class="comment">/// Short-hand for Flow&#39;s `String_view`.</span></div>
<div class="line"><a id="l00115" name="l00115"></a><span class="lineno"><a class="line" href="namespaceipc_1_1util.html#ae6ac47812a90d1287c61e0b7de7bc4f5">  115</a></span><span class="comment"></span><span class="keyword">using </span><a class="code hl_typedef" href="namespaceipc_1_1util.html#ae6ac47812a90d1287c61e0b7de7bc4f5">String_view</a> = <a class="code hl_typedef" href="namespaceipc_1_1util.html#ae6ac47812a90d1287c61e0b7de7bc4f5">flow::util::String_view</a>;<span class="comment"></span></div>
<div class="line"><a id="l00116" name="l00116"></a><span class="lineno">  116</span><span class="comment">/// Short-hand for Flow&#39;s `Fine_duration`.</span></div>
<div class="line"><a id="l00117" name="l00117"></a><span class="lineno"><a class="line" href="namespaceipc_1_1util.html#ac66141280c3b7295a86b65209f31cc58">  117</a></span><span class="comment"></span><span class="keyword">using </span><a class="code hl_typedef" href="namespaceipc_1_1util.html#ac66141280c3b7295a86b65209f31cc58">Fine_duration</a> = <a class="code hl_typedef" href="namespaceipc_1_1util.html#ac66141280c3b7295a86b65209f31cc58">flow::Fine_duration</a>;<span class="comment"></span></div>
<div class="line"><a id="l00118" name="l00118"></a><span class="lineno">  118</span><span class="comment">/// Short-hand for Flow&#39;s `Fine_time_pt`.</span></div>
<div class="line"><a id="l00119" name="l00119"></a><span class="lineno"><a class="line" href="namespaceipc_1_1util.html#aa3808edfc4d59bce4b9800d6a60026d3">  119</a></span><span class="comment"></span><span class="keyword">using </span><a class="code hl_typedef" href="namespaceipc_1_1util.html#aa3808edfc4d59bce4b9800d6a60026d3">Fine_time_pt</a> = <a class="code hl_typedef" href="namespaceipc_1_1util.html#aa3808edfc4d59bce4b9800d6a60026d3">flow::Fine_time_pt</a>;</div>
<div class="line"><a id="l00120" name="l00120"></a><span class="lineno">  120</span><span class="comment"></span> </div>
<div class="line"><a id="l00121" name="l00121"></a><span class="lineno">  121</span><span class="comment">/// Short-hand for polymorphic function (a-la `std::function&lt;&gt;`) that takes no arguments and returns nothing.</span></div>
<div class="line"><a id="l00122" name="l00122"></a><span class="lineno"><a class="line" href="namespaceipc_1_1util.html#a31e67d3a017477a04b313927e2f2c733">  122</a></span><span class="comment"></span><span class="keyword">using </span><a class="code hl_typedef" href="namespaceipc_1_1util.html#a31e67d3a017477a04b313927e2f2c733">Task</a> = <a class="code hl_typedef" href="namespaceipc_1_1util.html#a31e67d3a017477a04b313927e2f2c733">flow::async::Task</a>;</div>
<div class="line"><a id="l00123" name="l00123"></a><span class="lineno">  123</span><span class="comment"></span> </div>
<div class="line"><a id="l00124" name="l00124"></a><span class="lineno">  124</span><span class="comment">/**</span></div>
<div class="line"><a id="l00125" name="l00125"></a><span class="lineno">  125</span><span class="comment"> * Short-hand for an immutable blob somewhere in memory, stored as exactly a `void const *` and a `size_t`.</span></div>
<div class="line"><a id="l00126" name="l00126"></a><span class="lineno">  126</span><span class="comment"> *</span></div>
<div class="line"><a id="l00127" name="l00127"></a><span class="lineno">  127</span><span class="comment"> * ### How to use ###</span></div>
<div class="line"><a id="l00128" name="l00128"></a><span class="lineno">  128</span><span class="comment"> * We provide this alias as a stylistic short-hand, as it better suits various interfaces especially in</span></div>
<div class="line"><a id="l00129" name="l00129"></a><span class="lineno">  129</span><span class="comment"> * ipc::transport.  Nevertheless it&#39;s not meant to more than that; it&#39;s an attempt to abstract it away.</span></div>
<div class="line"><a id="l00130" name="l00130"></a><span class="lineno">  130</span><span class="comment"> *</span></div>
<div class="line"><a id="l00131" name="l00131"></a><span class="lineno">  131</span><span class="comment"> * That is to say, to work with these (create them, access them, etc.), do use the highly convenient</span></div>
<div class="line"><a id="l00132" name="l00132"></a><span class="lineno">  132</span><span class="comment"> * boost.asio buffer APIs which are well documented in boost.asio&#39;s docs.</span></div>
<div class="line"><a id="l00133" name="l00133"></a><span class="lineno">  133</span><span class="comment"> */</span></div>
<div class="line"><a id="l00134" name="l00134"></a><span class="lineno"><a class="line" href="namespaceipc_1_1util.html#ae0be7edba7e30ffa3f8b742af621f2ab">  134</a></span><span class="keyword">using </span><a class="code hl_typedef" href="namespaceipc_1_1util.html#ae0be7edba7e30ffa3f8b742af621f2ab">Blob_const</a> = boost::asio::const_buffer;</div>
<div class="line"><a id="l00135" name="l00135"></a><span class="lineno">  135</span><span class="comment"></span> </div>
<div class="line"><a id="l00136" name="l00136"></a><span class="lineno">  136</span><span class="comment">/**</span></div>
<div class="line"><a id="l00137" name="l00137"></a><span class="lineno">  137</span><span class="comment"> * Short-hand for an mutable blob somewhere in memory, stored as exactly a `void*` and a `size_t`.</span></div>
<div class="line"><a id="l00138" name="l00138"></a><span class="lineno">  138</span><span class="comment"> * @see ipc::util::Blob_const; usability notes in that doc header apply similarly here.</span></div>
<div class="line"><a id="l00139" name="l00139"></a><span class="lineno">  139</span><span class="comment"> */</span></div>
<div class="line"><a id="l00140" name="l00140"></a><span class="lineno"><a class="line" href="namespaceipc_1_1util.html#a6cb62ae434900f3a8915b33ec5d61a96">  140</a></span><span class="keyword">using </span><a class="code hl_typedef" href="namespaceipc_1_1util.html#a6cb62ae434900f3a8915b33ec5d61a96">Blob_mutable</a> = boost::asio::mutable_buffer;</div>
<div class="line"><a id="l00141" name="l00141"></a><span class="lineno">  141</span><span class="comment"></span> </div>
<div class="line"><a id="l00142" name="l00142"></a><span class="lineno">  142</span><span class="comment">/// Syntactic-sugary type for POSIX process ID (integer).</span></div>
<div class="line"><a id="l00143" name="l00143"></a><span class="lineno"><a class="line" href="namespaceipc_1_1util.html#a0c44028a45451ebf21f6af8e806b2682">  143</a></span><span class="comment"></span><span class="keyword">using </span><a class="code hl_typedef" href="namespaceipc_1_1util.html#a0c44028a45451ebf21f6af8e806b2682">process_id_t</a> = ::pid_t;</div>
<div class="line"><a id="l00144" name="l00144"></a><span class="lineno">  144</span><span class="comment"></span> </div>
<div class="line"><a id="l00145" name="l00145"></a><span class="lineno">  145</span><span class="comment">/// Syntactic-sugary type for POSIX user ID (integer).</span></div>
<div class="line"><a id="l00146" name="l00146"></a><span class="lineno"><a class="line" href="namespaceipc_1_1util.html#a6435c1b48ec8684c24ca406d1d17208e">  146</a></span><span class="comment"></span><span class="keyword">using </span><a class="code hl_typedef" href="namespaceipc_1_1util.html#a6435c1b48ec8684c24ca406d1d17208e">user_id_t</a> = ::uid_t;</div>
<div class="line"><a id="l00147" name="l00147"></a><span class="lineno">  147</span><span class="comment"></span> </div>
<div class="line"><a id="l00148" name="l00148"></a><span class="lineno">  148</span><span class="comment">/// Syntactic-sugary type for POSIX group ID (integer).</span></div>
<div class="line"><a id="l00149" name="l00149"></a><span class="lineno"><a class="line" href="namespaceipc_1_1util.html#a3f7d069ce0d23f73153da2e2559dc3d3">  149</a></span><span class="comment"></span><span class="keyword">using </span><a class="code hl_typedef" href="namespaceipc_1_1util.html#a3f7d069ce0d23f73153da2e2559dc3d3">group_id_t</a> = ::gid_t;</div>
<div class="line"><a id="l00150" name="l00150"></a><span class="lineno">  150</span><span class="comment"></span> </div>
<div class="line"><a id="l00151" name="l00151"></a><span class="lineno">  151</span><span class="comment">/// Tag type indicating an atomic open-if-exists-else-create operation.  @see #OPEN_OR_CREATE.</span></div>
<div class="line"><a id="l00152" name="l00152"></a><span class="lineno"><a class="line" href="namespaceipc_1_1util.html#a9571de958538d7a4a8649bbfecfac0b9">  152</a></span><span class="comment"></span><span class="keyword">using </span><a class="code hl_typedef" href="namespaceipc_1_1util.html#a9571de958538d7a4a8649bbfecfac0b9">Open_or_create</a> = bipc::open_or_create_t;</div>
<div class="line"><a id="l00153" name="l00153"></a><span class="lineno">  153</span><span class="comment"></span> </div>
<div class="line"><a id="l00154" name="l00154"></a><span class="lineno">  154</span><span class="comment">/// Tag type indicating an ideally-atomic open-if-exists-else-fail operation.  @see #OPEN_ONLY.</span></div>
<div class="line"><a id="l00155" name="l00155"></a><span class="lineno"><a class="line" href="namespaceipc_1_1util.html#a3e03491b5b2b5fac26551a220946d6e5">  155</a></span><span class="comment"></span><span class="keyword">using </span><a class="code hl_typedef" href="namespaceipc_1_1util.html#a3e03491b5b2b5fac26551a220946d6e5">Open_only</a> = bipc::open_only_t;</div>
<div class="line"><a id="l00156" name="l00156"></a><span class="lineno">  156</span><span class="comment"></span> </div>
<div class="line"><a id="l00157" name="l00157"></a><span class="lineno">  157</span><span class="comment">/// Tag type indicating a create-unless-exists-else-fail operation.  @see #CREATE_ONLY.</span></div>
<div class="line"><a id="l00158" name="l00158"></a><span class="lineno"><a class="line" href="namespaceipc_1_1util.html#a9d84c2bab504e6de32b20c77ca9723a2">  158</a></span><span class="comment"></span><span class="keyword">using </span><a class="code hl_typedef" href="namespaceipc_1_1util.html#a9d84c2bab504e6de32b20c77ca9723a2">Create_only</a> = bipc::create_only_t;</div>
<div class="line"><a id="l00159" name="l00159"></a><span class="lineno">  159</span><span class="comment"></span> </div>
<div class="line"><a id="l00160" name="l00160"></a><span class="lineno">  160</span><span class="comment">/// Short-hand for Unix (POSIX) permissions class.</span></div>
<div class="line"><a id="l00161" name="l00161"></a><span class="lineno"><a class="line" href="namespaceipc_1_1util.html#a1b398ae730d1e6040687cb2397115152">  161</a></span><span class="comment"></span><span class="keyword">using </span><a class="code hl_typedef" href="namespaceipc_1_1util.html#a1b398ae730d1e6040687cb2397115152">Permissions</a> = bipc::permissions;</div>
<div class="line"><a id="l00162" name="l00162"></a><span class="lineno">  162</span> </div>
<div class="line"><a id="l00163" name="l00163"></a><span class="lineno">  163</span><span class="comment">// Constants.</span></div>
<div class="line"><a id="l00164" name="l00164"></a><span class="lineno">  164</span><span class="comment"></span> </div>
<div class="line"><a id="l00165" name="l00165"></a><span class="lineno">  165</span><span class="comment">/// Tag value indicating an open-if-exists-else-create operation.</span></div>
<div class="line"><a id="l00166" name="l00166"></a><span class="lineno">  166</span><span class="comment"></span><span class="keyword">extern</span> <span class="keyword">const</span> <a class="code hl_typedef" href="namespaceipc_1_1util.html#a9571de958538d7a4a8649bbfecfac0b9">Open_or_create</a> <a class="code hl_variable" href="namespaceipc_1_1util.html#a5664539b3d75d6d10cdfebf6eac5382d">OPEN_OR_CREATE</a>;</div>
<div class="line"><a id="l00167" name="l00167"></a><span class="lineno">  167</span><span class="comment"></span> </div>
<div class="line"><a id="l00168" name="l00168"></a><span class="lineno">  168</span><span class="comment">/// Tag value indicating an atomic open-if-exists-else-fail operation.</span></div>
<div class="line"><a id="l00169" name="l00169"></a><span class="lineno">  169</span><span class="comment"></span><span class="keyword">extern</span> <span class="keyword">const</span> <a class="code hl_typedef" href="namespaceipc_1_1util.html#a3e03491b5b2b5fac26551a220946d6e5">Open_only</a> <a class="code hl_variable" href="namespaceipc_1_1util.html#a6a3a6ec85242d073df96978c63464078">OPEN_ONLY</a>;</div>
<div class="line"><a id="l00170" name="l00170"></a><span class="lineno">  170</span><span class="comment"></span> </div>
<div class="line"><a id="l00171" name="l00171"></a><span class="lineno">  171</span><span class="comment">/// Tag value indicating an atomic create-unless-exists-else-fail operation.</span></div>
<div class="line"><a id="l00172" name="l00172"></a><span class="lineno">  172</span><span class="comment"></span><span class="keyword">extern</span> <span class="keyword">const</span> <a class="code hl_typedef" href="namespaceipc_1_1util.html#a9d84c2bab504e6de32b20c77ca9723a2">Create_only</a> <a class="code hl_variable" href="namespaceipc_1_1util.html#ad1ca1cab79a35e1eb1c47037a0973cd8">CREATE_ONLY</a>;</div>
<div class="line"><a id="l00173" name="l00173"></a><span class="lineno">  173</span><span class="comment"></span> </div>
<div class="line"><a id="l00174" name="l00174"></a><span class="lineno">  174</span><span class="comment">/// A (default-cted) string.  May be useful for functions returning `const std::string&amp;`.</span></div>
<div class="line"><a id="l00175" name="l00175"></a><span class="lineno">  175</span><span class="comment"></span><span class="keyword">extern</span> <span class="keyword">const</span> std::string <a class="code hl_variable" href="namespaceipc_1_1util.html#aca6ca223759ca3e11d5834a323454afa">EMPTY_STRING</a>;</div>
<div class="line"><a id="l00176" name="l00176"></a><span class="lineno">  176</span> </div>
<div class="line"><a id="l00177" name="l00177"></a><span class="lineno">  177</span><span class="comment">// Free functions.</span></div>
<div class="line"><a id="l00178" name="l00178"></a><span class="lineno">  178</span><span class="comment"></span> </div>
<div class="line"><a id="l00179" name="l00179"></a><span class="lineno">  179</span><span class="comment">/**</span></div>
<div class="line"><a id="l00180" name="l00180"></a><span class="lineno">  180</span><span class="comment"> * Maps general Permissions_level specifier to low-level #Permissions value, when the underlying resource</span></div>
<div class="line"><a id="l00181" name="l00181"></a><span class="lineno">  181</span><span class="comment"> * is in the file-system and is either accessible (read-write in terms of file system) or inaccessible.</span></div>
<div class="line"><a id="l00182" name="l00182"></a><span class="lineno">  182</span><span class="comment"> * Examples of such resources are SHM pools (e.g., shm::classic::Pool_arena), bipc MQs (transport::Bipc_mq_handle),</span></div>
<div class="line"><a id="l00183" name="l00183"></a><span class="lineno">  183</span><span class="comment"> * POSIX MQs (transport::Posix_mq_handle).</span></div>
<div class="line"><a id="l00184" name="l00184"></a><span class="lineno">  184</span><span class="comment"> *</span></div>
<div class="line"><a id="l00185" name="l00185"></a><span class="lineno">  185</span><span class="comment"> * Please do not confuse this setting with the read-only/read-write dichotomy potentially specified each time such</span></div>
<div class="line"><a id="l00186" name="l00186"></a><span class="lineno">  186</span><span class="comment"> * a resource is opened for access (as is the case for SHM pools): the present mapping applies to a persistent</span></div>
<div class="line"><a id="l00187" name="l00187"></a><span class="lineno">  187</span><span class="comment"> * protection in the file system, not at runtime at the code writer&#39;s discretion.  The present permissions check</span></div>
<div class="line"><a id="l00188" name="l00188"></a><span class="lineno">  188</span><span class="comment"> * is performed at opening time; the runtime writability check each time a datum is written into the resource.</span></div>
<div class="line"><a id="l00189" name="l00189"></a><span class="lineno">  189</span><span class="comment"> *</span></div>
<div class="line"><a id="l00190" name="l00190"></a><span class="lineno">  190</span><span class="comment"> * @param permissions_lvl</span></div>
<div class="line"><a id="l00191" name="l00191"></a><span class="lineno">  191</span><span class="comment"> *        The value to translate.</span></div>
<div class="line"><a id="l00192" name="l00192"></a><span class="lineno">  192</span><span class="comment"> * @return The result.</span></div>
<div class="line"><a id="l00193" name="l00193"></a><span class="lineno">  193</span><span class="comment"> */</span></div>
<div class="line"><a id="l00194" name="l00194"></a><span class="lineno">  194</span><a class="code hl_typedef" href="namespaceipc_1_1util.html#a1b398ae730d1e6040687cb2397115152">Permissions</a> <a class="code hl_function" href="namespaceipc_1_1util.html#abda2ce5bcdbc26ca63d667b87818439c">shared_resource_permissions</a>(<a class="code hl_enumeration" href="namespaceipc_1_1util.html#a2ec0bfdddb41a1ef0403e4bb8967705d">Permissions_level</a> permissions_lvl);</div>
<div class="line"><a id="l00195" name="l00195"></a><span class="lineno">  195</span><span class="comment"></span> </div>
<div class="line"><a id="l00196" name="l00196"></a><span class="lineno">  196</span><span class="comment">/**</span></div>
<div class="line"><a id="l00197" name="l00197"></a><span class="lineno">  197</span><span class="comment"> * Utility that sets the permissions of the given resource (at the supplied file system path) to specified</span></div>
<div class="line"><a id="l00198" name="l00198"></a><span class="lineno">  198</span><span class="comment"> * POSIX value.  If the resource cannot be accessed (not found, permissions...) that system Error_code shall be</span></div>
<div class="line"><a id="l00199" name="l00199"></a><span class="lineno">  199</span><span class="comment"> * emitted.</span></div>
<div class="line"><a id="l00200" name="l00200"></a><span class="lineno">  200</span><span class="comment"> *</span></div>
<div class="line"><a id="l00201" name="l00201"></a><span class="lineno">  201</span><span class="comment"> * ### Rationale ###</span></div>
<div class="line"><a id="l00202" name="l00202"></a><span class="lineno">  202</span><span class="comment"> * It may seem unnecessary, particularly given that it sometimes (in our internal code, but I mention it</span></div>
<div class="line"><a id="l00203" name="l00203"></a><span class="lineno">  203</span><span class="comment"> * publicly for exposition purposes) is placed right after the</span></div>
<div class="line"><a id="l00204" name="l00204"></a><span class="lineno">  204</span><span class="comment"> * creation of the resource (file, SHM pool, POSIX MQ, shared mutex, etc.) -- where the same `perms` is supplied</span></div>
<div class="line"><a id="l00205" name="l00205"></a><span class="lineno">  205</span><span class="comment"> * to the creation-API, whichever is applicable.  The reason is that those APIs tend to make the corresponding OS</span></div>
<div class="line"><a id="l00206" name="l00206"></a><span class="lineno">  206</span><span class="comment"> * call (e.g., `open()`) which is bound by the &quot;process umask&quot; in POSIX/Linux; so for example if it&#39;s set to</span></div>
<div class="line"><a id="l00207" name="l00207"></a><span class="lineno">  207</span><span class="comment"> * the typical 022 (octal), then it&#39;s impossible to make the resource group- or all-writable, regardless of</span></div>
<div class="line"><a id="l00208" name="l00208"></a><span class="lineno">  208</span><span class="comment"> * `perms`.  set_resource_permissions() uses a technique that bypasses the umask thing.  Note that it does not make</span></div>
<div class="line"><a id="l00209" name="l00209"></a><span class="lineno">  209</span><span class="comment"> * any calls to change the umask to accomplish this.</span></div>
<div class="line"><a id="l00210" name="l00210"></a><span class="lineno">  210</span><span class="comment"> *</span></div>
<div class="line"><a id="l00211" name="l00211"></a><span class="lineno">  211</span><span class="comment"> * Note 1: Sometimes there is not even the creation-API argument for `perms`; in which case the rationale is even</span></div>
<div class="line"><a id="l00212" name="l00212"></a><span class="lineno">  212</span><span class="comment"> * more straightforward.</span></div>
<div class="line"><a id="l00213" name="l00213"></a><span class="lineno">  213</span><span class="comment"> *</span></div>
<div class="line"><a id="l00214" name="l00214"></a><span class="lineno">  214</span><span class="comment"> * Note 2: Sometimes there *is* that API... and (namely in boost.ipc at least) they actually took care to do this</span></div>
<div class="line"><a id="l00215" name="l00215"></a><span class="lineno">  215</span><span class="comment"> * (what we do here) themselves (via `fchmod()` and such)... so we don&#39;t need to; in fact I (ygoldfel) treated</span></div>
<div class="line"><a id="l00216" name="l00216"></a><span class="lineno">  216</span><span class="comment"> * it as valuable confirmation of the correctness of this maneuver.</span></div>
<div class="line"><a id="l00217" name="l00217"></a><span class="lineno">  217</span><span class="comment"> *</span></div>
<div class="line"><a id="l00218" name="l00218"></a><span class="lineno">  218</span><span class="comment"> * @param logger_ptr</span></div>
<div class="line"><a id="l00219" name="l00219"></a><span class="lineno">  219</span><span class="comment"> *        Logger to use for logging (WARNING, on error only).  Caller can themselves log further info if desired.</span></div>
<div class="line"><a id="l00220" name="l00220"></a><span class="lineno">  220</span><span class="comment"> * @param path</span></div>
<div class="line"><a id="l00221" name="l00221"></a><span class="lineno">  221</span><span class="comment"> *        Path to resource.  Symlinks are followed, and the target is the resource in question (not the symlink).</span></div>
<div class="line"><a id="l00222" name="l00222"></a><span class="lineno">  222</span><span class="comment"> * @param perms</span></div>
<div class="line"><a id="l00223" name="l00223"></a><span class="lineno">  223</span><span class="comment"> *        See other overload.</span></div>
<div class="line"><a id="l00224" name="l00224"></a><span class="lineno">  224</span><span class="comment"> * @param err_code</span></div>
<div class="line"><a id="l00225" name="l00225"></a><span class="lineno">  225</span><span class="comment"> *        See `flow::Error_code` docs for error reporting semantics.  #Error_code generated:</span></div>
<div class="line"><a id="l00226" name="l00226"></a><span class="lineno">  226</span><span class="comment"> *        see other overload; note that in addition file-not-found and the like are possible errors (in fact</span></div>
<div class="line"><a id="l00227" name="l00227"></a><span class="lineno">  227</span><span class="comment"> *        arguably the likeliest).</span></div>
<div class="line"><a id="l00228" name="l00228"></a><span class="lineno">  228</span><span class="comment"> */</span></div>
<div class="line"><a id="l00229" name="l00229"></a><span class="lineno">  229</span><span class="keywordtype">void</span> <a class="code hl_function" href="namespaceipc_1_1util.html#abbba79fcaee378f433e7ce3093e5c435">set_resource_permissions</a>(flow::log::Logger* logger_ptr, <span class="keyword">const</span> fs::path&amp; path,</div>
<div class="line"><a id="l00230" name="l00230"></a><span class="lineno">  230</span>                              <span class="keyword">const</span> <a class="code hl_typedef" href="namespaceipc_1_1util.html#a1b398ae730d1e6040687cb2397115152">Permissions</a>&amp; perms, <a class="code hl_typedef" href="namespaceipc.html#aa3192e586cc45d3e7c22463bf2760f89">Error_code</a>* err_code = 0);</div>
<div class="line"><a id="l00231" name="l00231"></a><span class="lineno">  231</span><span class="comment"></span> </div>
<div class="line"><a id="l00232" name="l00232"></a><span class="lineno">  232</span><span class="comment">/**</span></div>
<div class="line"><a id="l00233" name="l00233"></a><span class="lineno">  233</span><span class="comment"> * Identical to the other set_resource_permissions() overload but operates on a pre-opened Native_handle</span></div>
<div class="line"><a id="l00234" name="l00234"></a><span class="lineno">  234</span><span class="comment"> * (a/k/a handle, socket, file descriptor) to the resource in question.</span></div>
<div class="line"><a id="l00235" name="l00235"></a><span class="lineno">  235</span><span class="comment"> *</span></div>
<div class="line"><a id="l00236" name="l00236"></a><span class="lineno">  236</span><span class="comment"> * @param logger_ptr</span></div>
<div class="line"><a id="l00237" name="l00237"></a><span class="lineno">  237</span><span class="comment"> *        See other overload.</span></div>
<div class="line"><a id="l00238" name="l00238"></a><span class="lineno">  238</span><span class="comment"> * @param handle</span></div>
<div class="line"><a id="l00239" name="l00239"></a><span class="lineno">  239</span><span class="comment"> *        See above.  `handle.null() == true` causes undefined behavior (assertion may trip).</span></div>
<div class="line"><a id="l00240" name="l00240"></a><span class="lineno">  240</span><span class="comment"> *        Closed/invalid/etc. handle will yield civilized Error_code emission.</span></div>
<div class="line"><a id="l00241" name="l00241"></a><span class="lineno">  241</span><span class="comment"> * @param perms</span></div>
<div class="line"><a id="l00242" name="l00242"></a><span class="lineno">  242</span><span class="comment"> *        See other overload.</span></div>
<div class="line"><a id="l00243" name="l00243"></a><span class="lineno">  243</span><span class="comment"> * @param err_code</span></div>
<div class="line"><a id="l00244" name="l00244"></a><span class="lineno">  244</span><span class="comment"> *        See `flow::Error_code` docs for error reporting semantics.  #Error_code generated:</span></div>
<div class="line"><a id="l00245" name="l00245"></a><span class="lineno">  245</span><span class="comment"> *        system error codes if permissions cannot be set (invalid descriptor, un-opened descriptor, etc.).</span></div>
<div class="line"><a id="l00246" name="l00246"></a><span class="lineno">  246</span><span class="comment"> */</span></div>
<div class="line"><a id="l00247" name="l00247"></a><span class="lineno">  247</span><span class="keywordtype">void</span> <a class="code hl_function" href="namespaceipc_1_1util.html#abbba79fcaee378f433e7ce3093e5c435">set_resource_permissions</a>(flow::log::Logger* logger_ptr, <a class="code hl_struct" href="structipc_1_1util_1_1Native__handle.html">Native_handle</a> handle,</div>
<div class="line"><a id="l00248" name="l00248"></a><span class="lineno">  248</span>                              <span class="keyword">const</span> <a class="code hl_typedef" href="namespaceipc_1_1util.html#a1b398ae730d1e6040687cb2397115152">Permissions</a>&amp; perms, <a class="code hl_typedef" href="namespaceipc.html#aa3192e586cc45d3e7c22463bf2760f89">Error_code</a>* err_code = 0);</div>
<div class="line"><a id="l00249" name="l00249"></a><span class="lineno">  249</span><span class="comment"></span> </div>
<div class="line"><a id="l00250" name="l00250"></a><span class="lineno">  250</span><span class="comment">/**</span></div>
<div class="line"><a id="l00251" name="l00251"></a><span class="lineno">  251</span><span class="comment"> * Returns `true` if and only if the given process (by PID) is reported as running by the OS.</span></div>
<div class="line"><a id="l00252" name="l00252"></a><span class="lineno">  252</span><span class="comment"> * Caution: It may be running, but it may be a zombie; and/or it may be running now but dead shortly after</span></div>
<div class="line"><a id="l00253" name="l00253"></a><span class="lineno">  253</span><span class="comment"> * this function returns.  Use defensively.</span></div>
<div class="line"><a id="l00254" name="l00254"></a><span class="lineno">  254</span><span class="comment"> *</span></div>
<div class="line"><a id="l00255" name="l00255"></a><span class="lineno">  255</span><span class="comment"> * Implementation: It invokes POSIX `kill()` with the fake zero signal; this indicates the process *can*</span></div>
<div class="line"><a id="l00256" name="l00256"></a><span class="lineno">  256</span><span class="comment"> * be signaled and therefore exists.</span></div>
<div class="line"><a id="l00257" name="l00257"></a><span class="lineno">  257</span><span class="comment"> *</span></div>
<div class="line"><a id="l00258" name="l00258"></a><span class="lineno">  258</span><span class="comment"> * @param process_id</span></div>
<div class="line"><a id="l00259" name="l00259"></a><span class="lineno">  259</span><span class="comment"> *        The process ID of the process in question.</span></div>
<div class="line"><a id="l00260" name="l00260"></a><span class="lineno">  260</span><span class="comment"> * @return See above.</span></div>
<div class="line"><a id="l00261" name="l00261"></a><span class="lineno">  261</span><span class="comment"> */</span></div>
<div class="line"><a id="l00262" name="l00262"></a><span class="lineno">  262</span><span class="keywordtype">bool</span> <a class="code hl_function" href="namespaceipc_1_1util.html#a924cd56daf7eeaa0b07edb352367f9ec">process_running</a>(<a class="code hl_typedef" href="namespaceipc_1_1util.html#a0c44028a45451ebf21f6af8e806b2682">process_id_t</a> process_id);</div>
<div class="line"><a id="l00263" name="l00263"></a><span class="lineno">  263</span><span class="comment"></span> </div>
<div class="line"><a id="l00264" name="l00264"></a><span class="lineno">  264</span><span class="comment">/**</span></div>
<div class="line"><a id="l00265" name="l00265"></a><span class="lineno">  265</span><span class="comment"> * Syntactic-sugary helper that returns pointer to first byte in an immutable buffer, as `const uint8_t*`.</span></div>
<div class="line"><a id="l00266" name="l00266"></a><span class="lineno">  266</span><span class="comment"> *</span></div>
<div class="line"><a id="l00267" name="l00267"></a><span class="lineno">  267</span><span class="comment"> * @param blob</span></div>
<div class="line"><a id="l00268" name="l00268"></a><span class="lineno">  268</span><span class="comment"> *        The buffer.</span></div>
<div class="line"><a id="l00269" name="l00269"></a><span class="lineno">  269</span><span class="comment"> * @return See above.</span></div>
<div class="line"><a id="l00270" name="l00270"></a><span class="lineno">  270</span><span class="comment"> */</span></div>
<div class="line"><a id="l00271" name="l00271"></a><span class="lineno">  271</span><span class="keyword">const</span> uint8_t* <a class="code hl_function" href="namespaceipc_1_1util.html#a2bb38cee29dacbe56de5182221b45941">blob_data</a>(<span class="keyword">const</span> <a class="code hl_typedef" href="namespaceipc_1_1util.html#ae0be7edba7e30ffa3f8b742af621f2ab">Blob_const</a>&amp; blob);</div>
<div class="line"><a id="l00272" name="l00272"></a><span class="lineno">  272</span><span class="comment"></span> </div>
<div class="line"><a id="l00273" name="l00273"></a><span class="lineno">  273</span><span class="comment">/**</span></div>
<div class="line"><a id="l00274" name="l00274"></a><span class="lineno">  274</span><span class="comment"> * Syntactic-sugary helper that returns pointer to first byte in a mutable buffer, as `uint8_t*`.</span></div>
<div class="line"><a id="l00275" name="l00275"></a><span class="lineno">  275</span><span class="comment"> *</span></div>
<div class="line"><a id="l00276" name="l00276"></a><span class="lineno">  276</span><span class="comment"> * @param blob</span></div>
<div class="line"><a id="l00277" name="l00277"></a><span class="lineno">  277</span><span class="comment"> *        The buffer.</span></div>
<div class="line"><a id="l00278" name="l00278"></a><span class="lineno">  278</span><span class="comment"> * @return See above.</span></div>
<div class="line"><a id="l00279" name="l00279"></a><span class="lineno">  279</span><span class="comment"> */</span></div>
<div class="line"><a id="l00280" name="l00280"></a><span class="lineno">  280</span>uint8_t* <a class="code hl_function" href="namespaceipc_1_1util.html#a2bb38cee29dacbe56de5182221b45941">blob_data</a>(<span class="keyword">const</span> <a class="code hl_typedef" href="namespaceipc_1_1util.html#a6cb62ae434900f3a8915b33ec5d61a96">Blob_mutable</a>&amp; blob);</div>
<div class="line"><a id="l00281" name="l00281"></a><span class="lineno">  281</span> </div>
<div class="line"><a id="l00282" name="l00282"></a><span class="lineno">  282</span>} <span class="comment">// namespace ipc::util</span></div>
<div class="ttc" id="acommon_8hpp_html"><div class="ttname"><a href="common_8hpp.html">common.hpp</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html"><div class="ttname"><a href="namespaceipc_1_1util.html">ipc::util</a></div><div class="ttdoc">Flow-IPC module containing miscellaneous general-use facilities that ubiquitously used by ~all Flow-I...</div><div class="ttdef"><b>Definition:</b> <a href="default__init__allocator_8hpp_source.html#l00023">default_init_allocator.hpp:24</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_a0c44028a45451ebf21f6af8e806b2682"><div class="ttname"><a href="namespaceipc_1_1util.html#a0c44028a45451ebf21f6af8e806b2682">ipc::util::process_id_t</a></div><div class="ttdeci">::pid_t process_id_t</div><div class="ttdoc">Syntactic-sugary type for POSIX process ID (integer).</div><div class="ttdef"><b>Definition:</b> <a href="util__fwd_8hpp_source.html#l00143">util_fwd.hpp:143</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_a1b398ae730d1e6040687cb2397115152"><div class="ttname"><a href="namespaceipc_1_1util.html#a1b398ae730d1e6040687cb2397115152">ipc::util::Permissions</a></div><div class="ttdeci">bipc::permissions Permissions</div><div class="ttdoc">Short-hand for Unix (POSIX) permissions class.</div><div class="ttdef"><b>Definition:</b> <a href="util__fwd_8hpp_source.html#l00161">util_fwd.hpp:161</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_a2bb38cee29dacbe56de5182221b45941"><div class="ttname"><a href="namespaceipc_1_1util.html#a2bb38cee29dacbe56de5182221b45941">ipc::util::blob_data</a></div><div class="ttdeci">const uint8_t * blob_data(const Blob_const &amp;blob)</div><div class="ttdoc">Syntactic-sugary helper that returns pointer to first byte in an immutable buffer,...</div><div class="ttdef"><b>Definition:</b> <a href="ipc__core_2src_2ipc_2util_2util_8cpp_source.html#l00158">util.cpp:158</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_a2ec0bfdddb41a1ef0403e4bb8967705d"><div class="ttname"><a href="namespaceipc_1_1util.html#a2ec0bfdddb41a1ef0403e4bb8967705d">ipc::util::Permissions_level</a></div><div class="ttdeci">Permissions_level</div><div class="ttdoc">Simple specifier of desired access permissions, usually but not necessarily translated into a Permiss...</div><div class="ttdef"><b>Definition:</b> <a href="util__fwd_8hpp_source.html#l00093">util_fwd.hpp:94</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_a2ec0bfdddb41a1ef0403e4bb8967705da25bf1cdee66ff5f73914fd5b0ee996e9"><div class="ttname"><a href="namespaceipc_1_1util.html#a2ec0bfdddb41a1ef0403e4bb8967705da25bf1cdee66ff5f73914fd5b0ee996e9">ipc::util::Permissions_level::S_UNRESTRICTED</a></div><div class="ttdeci">@ S_UNRESTRICTED</div><div class="ttdoc">Allows access by all. Implies, as well, at least as much access as S_GROUP_ACCESS and thus S_USER_ACC...</div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_a2ec0bfdddb41a1ef0403e4bb8967705daa3e1d310128f18fe2f903bf3cba8849a"><div class="ttname"><a href="namespaceipc_1_1util.html#a2ec0bfdddb41a1ef0403e4bb8967705daa3e1d310128f18fe2f903bf3cba8849a">ipc::util::Permissions_level::S_USER_ACCESS</a></div><div class="ttdeci">@ S_USER_ACCESS</div><div class="ttdoc">Allows access by resource-owning user (in POSIX/Unix identified by UID) and no one else.</div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_a2ec0bfdddb41a1ef0403e4bb8967705daa5508fa6037b9c0926cf7eb20af97a6d"><div class="ttname"><a href="namespaceipc_1_1util.html#a2ec0bfdddb41a1ef0403e4bb8967705daa5508fa6037b9c0926cf7eb20af97a6d">ipc::util::Permissions_level::S_GROUP_ACCESS</a></div><div class="ttdeci">@ S_GROUP_ACCESS</div><div class="ttdoc">Allows access by resource-owning user's containing group(s) (in POSIX/Unix identified by GID) and no ...</div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_a2ec0bfdddb41a1ef0403e4bb8967705dac43e9194d6c0e9803ecabbf3cb4c97fa"><div class="ttname"><a href="namespaceipc_1_1util.html#a2ec0bfdddb41a1ef0403e4bb8967705dac43e9194d6c0e9803ecabbf3cb4c97fa">ipc::util::Permissions_level::S_NO_ACCESS</a></div><div class="ttdeci">@ S_NO_ACCESS</div><div class="ttdoc">Forbids all access, even by the creator's user. Most likely this would be useful for testing or debug...</div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_a31e67d3a017477a04b313927e2f2c733"><div class="ttname"><a href="namespaceipc_1_1util.html#a31e67d3a017477a04b313927e2f2c733">ipc::util::Task</a></div><div class="ttdeci">flow::async::Task Task</div><div class="ttdoc">Short-hand for polymorphic function (a-la std::function&lt;&gt;) that takes no arguments and returns nothin...</div><div class="ttdef"><b>Definition:</b> <a href="util__fwd_8hpp_source.html#l00122">util_fwd.hpp:122</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_a3e03491b5b2b5fac26551a220946d6e5"><div class="ttname"><a href="namespaceipc_1_1util.html#a3e03491b5b2b5fac26551a220946d6e5">ipc::util::Open_only</a></div><div class="ttdeci">bipc::open_only_t Open_only</div><div class="ttdoc">Tag type indicating an ideally-atomic open-if-exists-else-fail operation.</div><div class="ttdef"><b>Definition:</b> <a href="util__fwd_8hpp_source.html#l00155">util_fwd.hpp:155</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_a3f7d069ce0d23f73153da2e2559dc3d3"><div class="ttname"><a href="namespaceipc_1_1util.html#a3f7d069ce0d23f73153da2e2559dc3d3">ipc::util::group_id_t</a></div><div class="ttdeci">::gid_t group_id_t</div><div class="ttdoc">Syntactic-sugary type for POSIX group ID (integer).</div><div class="ttdef"><b>Definition:</b> <a href="util__fwd_8hpp_source.html#l00149">util_fwd.hpp:149</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_a5664539b3d75d6d10cdfebf6eac5382d"><div class="ttname"><a href="namespaceipc_1_1util.html#a5664539b3d75d6d10cdfebf6eac5382d">ipc::util::OPEN_OR_CREATE</a></div><div class="ttdeci">const Open_or_create OPEN_OR_CREATE</div><div class="ttdoc">Tag value indicating an open-if-exists-else-create operation.</div><div class="ttdef"><b>Definition:</b> <a href="ipc__core_2src_2ipc_2util_2util_8cpp_source.html#l00030">util.cpp:30</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_a6435c1b48ec8684c24ca406d1d17208e"><div class="ttname"><a href="namespaceipc_1_1util.html#a6435c1b48ec8684c24ca406d1d17208e">ipc::util::user_id_t</a></div><div class="ttdeci">::uid_t user_id_t</div><div class="ttdoc">Syntactic-sugary type for POSIX user ID (integer).</div><div class="ttdef"><b>Definition:</b> <a href="util__fwd_8hpp_source.html#l00146">util_fwd.hpp:146</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_a6a3a6ec85242d073df96978c63464078"><div class="ttname"><a href="namespaceipc_1_1util.html#a6a3a6ec85242d073df96978c63464078">ipc::util::OPEN_ONLY</a></div><div class="ttdeci">const Open_only OPEN_ONLY</div><div class="ttdoc">Tag value indicating an atomic open-if-exists-else-fail operation.</div><div class="ttdef"><b>Definition:</b> <a href="ipc__core_2src_2ipc_2util_2util_8cpp_source.html#l00031">util.cpp:31</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_a6cb62ae434900f3a8915b33ec5d61a96"><div class="ttname"><a href="namespaceipc_1_1util.html#a6cb62ae434900f3a8915b33ec5d61a96">ipc::util::Blob_mutable</a></div><div class="ttdeci">boost::asio::mutable_buffer Blob_mutable</div><div class="ttdoc">Short-hand for an mutable blob somewhere in memory, stored as exactly a void* and a size_t.</div><div class="ttdef"><b>Definition:</b> <a href="util__fwd_8hpp_source.html#l00140">util_fwd.hpp:140</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_a924cd56daf7eeaa0b07edb352367f9ec"><div class="ttname"><a href="namespaceipc_1_1util.html#a924cd56daf7eeaa0b07edb352367f9ec">ipc::util::process_running</a></div><div class="ttdeci">bool process_running(process_id_t process_id)</div><div class="ttdoc">Returns true if and only if the given process (by PID) is reported as running by the OS.</div><div class="ttdef"><b>Definition:</b> <a href="ipc__core_2src_2ipc_2util_2util_8cpp_source.html#l00134">util.cpp:134</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_a9571de958538d7a4a8649bbfecfac0b9"><div class="ttname"><a href="namespaceipc_1_1util.html#a9571de958538d7a4a8649bbfecfac0b9">ipc::util::Open_or_create</a></div><div class="ttdeci">bipc::open_or_create_t Open_or_create</div><div class="ttdoc">Tag type indicating an atomic open-if-exists-else-create operation.</div><div class="ttdef"><b>Definition:</b> <a href="util__fwd_8hpp_source.html#l00152">util_fwd.hpp:152</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_a9d84c2bab504e6de32b20c77ca9723a2"><div class="ttname"><a href="namespaceipc_1_1util.html#a9d84c2bab504e6de32b20c77ca9723a2">ipc::util::Create_only</a></div><div class="ttdeci">bipc::create_only_t Create_only</div><div class="ttdoc">Tag type indicating a create-unless-exists-else-fail operation.</div><div class="ttdef"><b>Definition:</b> <a href="util__fwd_8hpp_source.html#l00158">util_fwd.hpp:158</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_aa3808edfc4d59bce4b9800d6a60026d3"><div class="ttname"><a href="namespaceipc_1_1util.html#aa3808edfc4d59bce4b9800d6a60026d3">ipc::util::Fine_time_pt</a></div><div class="ttdeci">flow::Fine_time_pt Fine_time_pt</div><div class="ttdoc">Short-hand for Flow's Fine_time_pt.</div><div class="ttdef"><b>Definition:</b> <a href="util__fwd_8hpp_source.html#l00119">util_fwd.hpp:119</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_abbba79fcaee378f433e7ce3093e5c435"><div class="ttname"><a href="namespaceipc_1_1util.html#abbba79fcaee378f433e7ce3093e5c435">ipc::util::set_resource_permissions</a></div><div class="ttdeci">void set_resource_permissions(flow::log::Logger *logger_ptr, const fs::path &amp;path, const Permissions &amp;perms, Error_code *err_code)</div><div class="ttdoc">Utility that sets the permissions of the given resource (at the supplied file system path) to specifi...</div><div class="ttdef"><b>Definition:</b> <a href="ipc__core_2src_2ipc_2util_2util_8cpp_source.html#l00046">util.cpp:46</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_abda2ce5bcdbc26ca63d667b87818439c"><div class="ttname"><a href="namespaceipc_1_1util.html#abda2ce5bcdbc26ca63d667b87818439c">ipc::util::shared_resource_permissions</a></div><div class="ttdeci">Permissions shared_resource_permissions(Permissions_level permissions_lvl)</div><div class="ttdoc">Maps general Permissions_level specifier to low-level Permissions value, when the underlying resource...</div><div class="ttdef"><b>Definition:</b> <a href="ipc__core_2src_2ipc_2util_2util_8cpp_source.html#l00037">util.cpp:37</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_ac66141280c3b7295a86b65209f31cc58"><div class="ttname"><a href="namespaceipc_1_1util.html#ac66141280c3b7295a86b65209f31cc58">ipc::util::Fine_duration</a></div><div class="ttdeci">flow::Fine_duration Fine_duration</div><div class="ttdoc">Short-hand for Flow's Fine_duration.</div><div class="ttdef"><b>Definition:</b> <a href="util__fwd_8hpp_source.html#l00117">util_fwd.hpp:117</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_aca6ca223759ca3e11d5834a323454afa"><div class="ttname"><a href="namespaceipc_1_1util.html#aca6ca223759ca3e11d5834a323454afa">ipc::util::EMPTY_STRING</a></div><div class="ttdeci">const std::string EMPTY_STRING</div><div class="ttdoc">A (default-cted) string. May be useful for functions returning const std::string&amp;.</div><div class="ttdef"><b>Definition:</b> <a href="ipc__core_2src_2ipc_2util_2util_8cpp_source.html#l00033">util.cpp:33</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_ad1ca1cab79a35e1eb1c47037a0973cd8"><div class="ttname"><a href="namespaceipc_1_1util.html#ad1ca1cab79a35e1eb1c47037a0973cd8">ipc::util::CREATE_ONLY</a></div><div class="ttdeci">const Create_only CREATE_ONLY</div><div class="ttdoc">Tag value indicating an atomic create-unless-exists-else-fail operation.</div><div class="ttdef"><b>Definition:</b> <a href="ipc__core_2src_2ipc_2util_2util_8cpp_source.html#l00032">util.cpp:32</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_ae0be7edba7e30ffa3f8b742af621f2ab"><div class="ttname"><a href="namespaceipc_1_1util.html#ae0be7edba7e30ffa3f8b742af621f2ab">ipc::util::Blob_const</a></div><div class="ttdeci">boost::asio::const_buffer Blob_const</div><div class="ttdoc">Short-hand for an immutable blob somewhere in memory, stored as exactly a void const * and a size_t.</div><div class="ttdef"><b>Definition:</b> <a href="util__fwd_8hpp_source.html#l00134">util_fwd.hpp:134</a></div></div>
<div class="ttc" id="anamespaceipc_1_1util_html_ae6ac47812a90d1287c61e0b7de7bc4f5"><div class="ttname"><a href="namespaceipc_1_1util.html#ae6ac47812a90d1287c61e0b7de7bc4f5">ipc::util::String_view</a></div><div class="ttdeci">flow::util::String_view String_view</div><div class="ttdoc">Short-hand for Flow's String_view.</div><div class="ttdef"><b>Definition:</b> <a href="util__fwd_8hpp_source.html#l00115">util_fwd.hpp:115</a></div></div>
<div class="ttc" id="anamespaceipc_html_a4ccdeed058222c635745a4dc830e99f7a6fba12db09e5bebfaa04f6372c41c2cf"><div class="ttname"><a href="namespaceipc.html#a4ccdeed058222c635745a4dc830e99f7a6fba12db09e5bebfaa04f6372c41c2cf">ipc::Log_component::S_END_SENTINEL</a></div><div class="ttdeci">@ S_END_SENTINEL</div><div class="ttdoc">CAUTION – see ipc::Log_component doc header for directions to find actual members of this enum class.</div></div>
<div class="ttc" id="anamespaceipc_html_aa3192e586cc45d3e7c22463bf2760f89"><div class="ttname"><a href="namespaceipc.html#aa3192e586cc45d3e7c22463bf2760f89">ipc::Error_code</a></div><div class="ttdeci">flow::Error_code Error_code</div><div class="ttdoc">Short-hand for flow::Error_code which is very common.</div><div class="ttdef"><b>Definition:</b> <a href="common_8hpp_source.html#l00298">common.hpp:298</a></div></div>
<div class="ttc" id="anative__handle_8hpp_html"><div class="ttname"><a href="native__handle_8hpp.html">native_handle.hpp</a></div></div>
<div class="ttc" id="astructipc_1_1util_1_1Native__handle_html"><div class="ttname"><a href="structipc_1_1util_1_1Native__handle.html">ipc::util::Native_handle</a></div><div class="ttdoc">A monolayer-thin wrapper around a native handle, a/k/a descriptor a/k/a FD.</div><div class="ttdef"><b>Definition:</b> <a href="native__handle_8hpp_source.html#l00062">native_handle.hpp:63</a></div></div>
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